Soft filled prosthesis shell with variable texture

ABSTRACT

A soft prosthetic implant, such as a silicone breast implant, is provided. The implant has a variety of different surfaces, for example, different textures, located on different areas of the outer surface of the implant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/714,058, filed on May 15, 2015, which claims priority to, and thebenefit of, U.S. Provisional Patent Application No. 61/994,772, filed onMay 16, 2014, the entire disclosure of each of which is incorporatedherein by this specific reference.

FIELD OF THE INVENTION

The present invention relates to soft prosthetic implants and, moreparticularly, to textured exterior surfaces of such implants, forinstance, breast implants.

BACKGROUND OF THE INVENTION

Implantable prostheses are commonly used to replace or augment bodytissue. In the case of breast cancer, it is sometimes necessary toremove some or all of the mammary gland and surrounding tissue, whichcreates a void that can be filled with an implantable prosthesis. Theimplant serves to support surrounding tissue and to maintain theappearance of the body. The restoration of the normal appearance of thebody has an extremely beneficial psychological effect on post-operativepatients, eliminating much of the shock and depression that oftenfollows extensive surgical procedures. Implantable prostheses are alsoused more generally for restoring the normal appearance of soft tissuein various areas of the body, such as the buttocks, chin, calf, etc.

Soft implantable prostheses typically include a relatively thin andflexible envelope or shell made of vulcanized (cured) siliconeelastomer. The shell is filled either with a silicone gel or with anormal saline solution. The filling of the shell takes place before orafter the shell is inserted through an incision in the patient.

In the United States, women can choose between two different types ofbreast implant shell surfaces: a smooth surface and a textured surface.The surgeon generally recommends the type of surface based on his or hertechnique and the shape of the breast implant chosen to best fit theneeds of each patient.

Breast implants are not without complications, one of which is termedcapsular contracture. This is a complication that occurs uponcontraction of a fibrous outer capsule that forms around the implant,which tends to render the implant spherical and stiff and aestheticallyundesirable. According to the United States Food and DrugAdministration's (FDA) Breast Implant Consumer Handbook (2004), theliterature shows that textured surface breast implants may decrease thecapsular contracture rate.

Texturing may be provided in a number of ways. Silicone gel breastimplants covered with a thin layer of textured polyurethane foam enjoyedconsiderable popularity in the 1980s because of their remarkableresistance to the early development of fibrous capsular contracture. Forexample, U.S. Pat. No. 3,293,663 describes a soft gel-filled prosthesiswith a porous polyester fabric on the back side for tissue ingrowth andanchoring to the chest wall. Although these devices are no longeravailable in the U.S. because of regulatory constraint, their medicaland commercial success stimulated interest in surface texturization ofsilicone implants.

Despite many advances in the development of safe and comfortableprosthetic implants, there remains room for improvement.

SUMMARY OF THE INVENTION

The present invention provides a prosthesis suitable for implantation ina human being, for example, a breast implant suitable for use inreconstruction or augmentation of the human breast. The prosthesisgenerally comprises an implantable member, for example, an elastomericshell that is filled or is fillable with a liquid or gel. Theimplantable member has an exterior surface including one or morefixation regions defined thereon and configured, positioned orstructured to provide enhanced or controlled tissue ingrowth oradhesion.

In accordance with one aspect of the invention, the fixation surfacesare discrete surface portions extending across an anterior face or aposterior face of the implant. These fixation surfaces, sometimes hereinreferred to as “fixation regions,” are generally defined by a texture,roughness or sheen that is different from a texture, roughness or sheenof adjacent surface portions of the implant.

In some embodiments, the fixation regions have an increased or enhancedtexture relative to the balance of the anterior face or posterior faceof the implant. In other words, the balance of the exterior surface maybe relatively less textured than the fixation regions. In someembodiments, the fixation regions are textured and adjacent surfaces,for example, the surface or surfaces that are not defined by thefixation regions, are substantially less textured, or are relativelysmooth.

The prosthesis may be structured to encourage enhanced tissue ingrowthor adhesion at the fixation regions, relative to an otherwise identicalsurface without such texture, roughness or sheen.

In one aspect of the invention, the fixation regions are positionedand/or configured such that the prosthesis, after implantation in thebody, moves more naturally with the human body, for example, in relativeunity with the muscles of the body. It is contemplated that because theimplant moves more naturally with the human body, the implant may beless prone to wear resulting from material stresses relative toconventional implants, for example, implants without such fixationregions. Furthermore, it is contemplated that the present implants willbe more comfortable to the patient in that they will move more naturallywith the body.

In a more specific aspect of the invention, the fixation regions may belocated at specific regions on an anterior face of the shell, that is, aface of the shell which faces the front of the human body when theimplant has been appropriately implanted in the human body.Alternatively or additionally, one or more discrete fixation surfacesmay be provided on a periphery of the shell (e.g. circumferentially)and/or on the posterior face of the shell, that is, the face of theshell that faces the back of the human body when the implant has beenimplanted in the human body.

In an even more specific aspect of the invention, the fixation regionscomprise at least one elongated region located on the anterior face ofthe shell. The at least one elongated region may be, for example, aband-shaped region or alternatively, a plurality of band shaped regionshaving enhanced texture, roughness or sheen.

In another broad aspect of the invention, the prosthesis comprises abreast implant having a shell including a fixation region having a firsttexture and a balance of the shell surface having a second texture thatis different from the first texture. In other words, in some embodimentsof the invention, the entire, or substantially entire, exterior of thebreast implant shell is a textured surface with specific regions thereofhaving a greater degree of texturing relative to the remaining portionsof the textured surface.

It is contemplated that such different texturing will stimulate orencourage different degrees of tissue ingrowth or adhesion at thedifferent fixation regions. For example, in one embodiment, the firstfixation region is located on a posterior face of the implant and thesecond fixation region is located on an anterior face of the implant.The first fixation region may be defined by a texture that is moreconducive to tissue interaction and adhesion whereas the second fixationregion may be defined by a texture that is relatively less conducive totissue interaction and adhesion.

In yet another aspect of the invention, the prosthesis comprises a shellhaving an exterior structured to contact tissue, the shell including afirst fixation surface having a first open cell structure, and a secondfixation surface having a second open cell structure different than saidfirst open cell structure. In addition, the first fixation surface andthe second fixation surface are positioned to encourage respectivelydifferent degrees of tissue ingrowth or tissue adhesion by the body at abody-shell interface.

For example, the first open cell structure comprises relatively largeopen cells and the second open cell structure comprises relativelysmaller open cells. Alternatively or additionally, the first open cellstructure may comprise a first distribution of cells and the second opencell structure comprises a second distribution of cells wherein thefirst distribution of cells is relatively more dense than the seconddistribution of cells.

In yet another specific aspect of the invention, the first open cellstructure comprises relatively large rounded open cells and the secondopen cell structure comprises relatively small rounded open cells.Alternatively, the first open cell structure comprises relativelyrounded open cells and the second open cell structure comprisesrelatively angular open cells.

Advantageously, in accordance with certain embodiments, the first andsecond fixation surfaces are positioned and structured to be at leastsomewhat effective to disrupt or disorient capsular tissue formationabout the prosthesis after the prosthesis has been implanted in thebody.

The present invention further provides a breast prosthesis shell forimplantation in a human being, the shell manufactured by the steps ofproviding a shell precursor; applying a layer of silicone elastomer tothe shell precursor, applying solid particles of a first configurationto a portion of the layer of silicone elastomer and applying solidparticles of a second configuration to another portion of the layer ofsilicone elastomer before the layer is fully cured. After the layerincluding the solid particles embedded therein is cured, the solidparticles are then dissolved, for example, by means of a solvent thatdoes not dissolve the silicone elastomer to any appreciable extent. Theresulting elastomer shell includes a first open cell texture regionformed by said application of the solid particles of the firstconfiguration, and a second open cell texture region formed by saidapplication of the solid particles of the second configuration.

In yet another aspect of the invention, a method of augmenting orreconstructing a breast of a human being is provided. The methodgenerally comprises providing an implantable member including at leastone elongated fixation region as described elsewhere herein andimplanting the implantable member into a breast of a human being suchthat the fixation region generally aligns with one of the pectoralismajor muscle group and the pectoralis minor muscle group. The method mayfurther comprise filling the implantable member with a liquid or gelprior to or after the implanting step.

A further understanding of the nature and advantages of the presentinvention are set forth in the following description and claims,particularly when considered in conjunction with the accompanyingdrawings in which like parts bear like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become appreciatedas the same become better understood with reference to thespecification, claims, and appended drawings wherein:

FIGS. 1A-1B are a front view and a side elevational view, respectively,of an exemplary round breast implant of the present invention;

FIGS. 2A-2B are a front view and side elevational view, respectively, ofan exemplary shaped breast implant of the present invention;

FIGS. 3A and 3B are schematic views of a woman's upper torso showing,alignment of the pectoralis major muscle group and the pectoralis minormuscle group, respectively;

FIGS. 4A and 4B are vertical sectional views through a woman's breastand adjacent chest anatomy showing, respectively, subglandular andsubmuscular placement of a breast implant;

FIGS. 5A-5B are front and side elevational views of an exemplary roundbreast implant of the present invention having a generally elongated orband-shaped fixation surface;

FIGS. 6A-6B are front and side elevational views of an exemplary shapedbreast implant of the present invention having a generally elongated orband-shaped fixation surface;

FIG. 7 is a front elevational view of another breast implant inaccordance with the invention including a first fixation region having afirst texture and a second fixation region having a second texturedifferent from the first texture;

FIGS. 8A and 8B are front and rear elevational views of an exemplaryround breast implant of the present invention having a front texture anda rear texture that are different from one another;

FIG. 9 is a side view of a breast implant in accordance with anotherembodiment of the invention;

FIG. 10 is a side view of a breast implant in accordance with yetanother embodiment of the invention; and

FIG. 11 is a side view of a breast implant in accordance with yet afurther embodiment of the invention.

DETAILED DESCRIPTION

The present invention provides a saline- or gel-filled soft implantshell, preferably a silicone elastomer shell, with a fixation surfaceover an exterior portion. The primary application for such soft implantsis to reconstruct or augment the female breast. Other potentialapplications are implants for the buttocks, testes, or calf, among otherareas.

The terms “fixation surface” or “fixation region”, as used herein,generally refer to a region or portion of an exterior surface of animplant which is positioned, structured or adapted to encourage tissueingrowth or adhesion at a body/implant interface. For example, afixation region may be a texture, roughness or sheen that is distinctfrom, for example, more pronounced than, adjacent surfaces of theimplant which do not encourage tissue ingrowth of adhesion to the samedegree as the fixation region. For example, other regions or surfaces ofthe implant exterior may be relatively smooth or less textured relativeto the fixation regions.

Such a fixation region may be formed by any suitable means, for example,but not limited to, a salt removal process such as described in U.S.Pat. No. 5,007,929, with appropriate changes being made. Alternatively,the fixation surfaces may be formed by separate textured elements suchas textured patches or films adhered to the outside of an otherwise“smooth” or less textured implant. Still, another method for forming thediscrete fixation regions may be by using a relatively roughened surfaceportion of a mold used to form the implant. Another method for formingthe present fixation regions includes texturing the exterior of theimplant after formation. The present invention should not be consideredlimited to any particular type of texturing or fixation surface, thoughthere might be certain advantages with one or more of these techniques.

Turning now to the Figures, FIGS. 1A and 1B are front and sideelevational views of an exemplary round breast implant 20. Generally,the implant 20 comprises an exterior surface defined by a relativelysmooth anterior face 21, a textured posterior face 22 and a texturedperipheral region 24 located between the anterior face 21 and theposterior face 22. The relatively smooth anterior face may be arelatively less textured surface (relative to texture of posterior face22), such as, for example, a fine textured surface or even a mattefinish. In some embodiments, the implant 20 has a relatively smoothposterior face, a textured anterior face and a textured or smoothperipheral region. The fixation surfaces 22, 24 themselves may havediffering degrees of texturing. The diameter D and front-to-backthickness T of the implant are shown and vary depending on the patient'schest size and aesthetic considerations.

In the shown embodiment, the rear fixation surface 22 extends to theapex 26 or generatrix of the convex outer periphery of the implant 20.The peripheral fixation surface 24 continues forward a short distance Sonto the anterior or front surface 21. In some embodiments, the distanceS is between about 10% and about 30% of the thickness T. In someembodiments, the peripheral fixation surface 24 extends substantiallyentirely around the periphery of the implant 20, such that the implant20 is axi-symmetric. In other embodiments, the peripheral fixationsurface 24 may be abbreviated so as to extend around only a portion ofthe periphery of the implant, such as the inferior or superior half, orthe peripheral fixation surface may be broken up into spaced apartsegments. In some embodiments, the peripheral fixation surface 24comprises substantially evenly spaced segments resulting in alternatingsmooth and textured areas.

FIGS. 2A-2B illustrate an exemplary shaped breast implant 30 of thepresent invention having an inferior frontal lobe 32 simulating anatural breast. Like implant 20, implant 30 includes a rear fixationsurface 34 and a peripheral fixation surface 36. The width W, height H,and front-to-back thickness T of the implant are shown. If the frontprojection is round, then W=H, otherwise W may be greater than or lessthan H. When provided with a natural shape, the implant 30 has a properorientation, namely with the inferior lobe 32 at the lower center.Accordingly, the peripheral fixation surface 36 may extend completelyaround the periphery of the implant, or may be formed in discrete areasand be oriented relative to the natural shape of the implant. Forexample, the peripheral fixation surface 36 may be formed only aroundthe inferior or lower half of the implant, or may be formed only on thesides.

FIG. 3A illustrates a woman's upper torso schematically showing on oneside placement and alignment of the pectoralis major muscle group, whileFIG. 3B illustrates the placement and alignment of the pectoralis minormuscle group. These two muscle groups overlap one another and extendgenerally from the shoulder or collarbone region to the rib cageunderneath the breast. One aspect of the present invention is to providean implant including fixation surfaces such as described elsewhereherein, which are substantially aligned with these muscle groups whenthe implant is placed in the body.

While not wishing to be bound by any specific theory of operation, theregions or lines of contact of the implant with the primary chestmuscles experience greater movement than other areas of the implant notinterfacing the muscles. It is believed by the present inventors that byproviding a fixation region of the implant that is substantiallycoincident with or in substantial alignment with one or more of thesemuscle groups is more likely to remain secured (i.e., they move with themuscle). In addition, it is contemplated that such discrete fixationregions may provide the benefit of disrupting capsule formation and/orreducing the potential for capsular contraction.

FIG. 4A is a vertical sectional view through a woman's breast andadjacent chest anatomy showing a subglandular placement of a breastimplant 40. The implant 40 is positioned over the top of the pectoralismajor muscle group 42, which in turn overlays the pectoralis minormuscle group 44. The chest wall 48 showing a plurality of ribs 50 isalso indicated underneath the pectoralis minor muscle 44. FIG. 4B is avertical sectional view as in FIG. 4A but showing a submuscularplacement of the implant 40, underneath the pectoralis major musclegroup 42. Both these two implant placements are utilized primarilydepending on the surgeon's clinical determination, sometimes influencedby a dialogue between patient and the surgeon and desired outcome.Depending on the implant placements, the implant 40 may be in contactwith one or both muscle groups. In some embodiments of the invention,the implant includes substantially elongated fixation regions asdescribed and shown herein, and said fixation regions being insubstantial alignment with the appropriate muscle group which interfacethe implant when the implant is placed in the body.

For example, FIGS. 5A-5B are front and side elevational views of anexemplary round breast implant 60 of the present invention having aposterior face 62, a peripheral region 64, and an anterior faceincluding an elongated or band-shaped fixation region 66. Theband-shaped fixation region 66 extends generally along a diagonal angleand commences at the front border of the peripheral fixation surface 64.The illustrated embodiment, the fixation region 66 has a substantiallyconstant width W as seen from the front in FIG. 5A. In one embodiment,the width W is between about 1 mm to about 20 mm, for example, betweenabout 2 mm to about 15 mm. Alternatively, although not shown, thefixation region 66 may have a configuration that is other than aconstant width.

In one embodiment, the band-shaped fixation surface 66 is generallyoriented or aligned with either the pectoralis major muscle group orpectoralis minor muscle group when the implant is implanted in thebreast. For instance, if the implant 60 is destined for a submuscularplacement such as in FIG. 4B, the fixation surface 66 may be oriented tobe generally aligned with the pectoralis major muscle group, as seen inFIG. 3A. Alternatively, the angle at which the insertion surface 66 isoriented may be an approximation of the average angle of the pectoralismajor and pectoralis minor muscle groups. In this way, the implant 60has a fixation surface 66 to encourage tissue ingrowth or adhesion alongthe major stress lines of the implant. Preferably, the fixation surface66 is angled between about 30-60° with respect to a vertical planethrough the implant 60. Of course, if the implant 60 is round as shown,the fixation surface 66 itself defines the orientation thereof. In oneembodiment, the band-shaped fixation surface 66 is centered about thecenter of the implant 60, therefore creating two symmetric orientationsabout 180° apart. This arrangement facilitates implant by providing twopossible orientations for the surgeon.

The band-shaped fixation region 66 may extend substantially across theanterior face of the implant and may be defined by a texture that isdifferent from a balance of the anterior face. The fixation region 66may also have a different texture, for example, a more pronounced ormore aggressive texture, than the rear fixation surface 62 or peripheralsurface 64.

FIGS. 6A-6B illustrate another exemplary shaped breast implant 70 of thepresent invention. The implant 70 again features a rear fixation surface72, a peripheral fixation surface 74, and a plurality of separateband-shaped fixation surfaces 76 a, 76 b, 76 c. These discrete fixationsurfaces 76 a, 76 b, 76 c are positioned or configured to align with oneor more of the muscle groups described above. For example, the threefixation surfaces 76 a, 76 b, 76 c may be generally oriented relative tothe fan-shaped pectoralis minor muscle group. Because the shaped implant70 is orientation-specific, proper placement of the implant orients thefixation surfaces 76 a, 76 b, 76 c with the particular muscle group. Asmentioned above, the various fixation surfaces 72, 74, 76 a, 76 b, and76 c may be formed with a similar level of roughness, or some may beless textured, such as with a matte finish. For instance, the rear andperipheral fixation surfaces 72, 74 may have a fine, matte finish, whilethe frontal fixation surfaces 76 a, 76 b, 76 c are more denselytextured. The present invention contemplates all permutations oftexturing choices.

In cross-section, the textured implant shells of the present inventionmay be single- or multi-layered. The overall thickness of the texturedimplant shell wall may be somewhat greater than a similar smooth-walledshell because of the extra layers of texture.

Turning now to FIG. 7, an anterior (front) view of another breastimplant of the present invention is shown generally at 110. The implant110 includes a shell 112 having an exterior surface including a firstfixation region 114 having a first texture 116 and a second fixationregion 118 having a second texture 122 that is different from the firsttexture 116. In the shown embodiment, the first texture 116 is a more“aggressive” texture than the second texture 122. The first texture 116is structured to encourage a greater degree of tissue interaction thanthe second texture 122.

In lieu of the second texture 122, it is contemplated that the secondfixation region 118, and perhaps the entire balance of the exterior ofthe shell 112, may be a low sheen surface, for example, a matte finish.

Turning now to FIGS. 8A and 8B, anterior (front) and posterior (rear)views, respectively, of another breast implant in accordance with theinvention are shown generally at 210. The implant 210 includes a shell212 having an anterior face 212 a and a posterior face 212 b, andincluding a first fixation region 214 having a first texture 216 and asecond fixation region 218 having a second texture 222 that is differentfrom the first texture 216. In the shown embodiment, the first texture216 may encompass the entire, or substantially entire, anterior face 212a of the implant 210. The first texture 216 is defined by a firstdistribution of pores, crevices or caverns that is relatively less densethan that of the second texture 222. The second texture 222, which mayencompass the entire, or substantially entire, posterior face 221 b ofthe implant 210, may be structured to encourage a greater degree oftissue interaction and adhesion than that of the first texture 216.

In another aspect of the invention, a breast implant is provided, theimplant comprising an elastomeric shell comprising a first region and asecond region, and an outer surface, the first region defined by a firsttextured surface of the shell; and the second region defined by a secondsurface of the shell that is different from the first textured surfaceof the shell. In some embodiments, the first textured surface issubstantially defined by interconnected pores extending a depth ofbetween about 0.2 mm to about 5.0 mm into the shell outer surface.

In some embodiments, the interconnected pores of the first texturedsurface extend at least about two to about five pore diameters deep intothe shell outer surface. Such a surface can be made using alternatingporogens and elastomer on the surface of the breast implant shell, togain the desired depth of porosity, fusing the porogens, and removingthe porogens to leave the interconnected porous structure that overliesa non-porous layer of the shell which contains the silicone gel filling.

For example, the pores may be made with dissolvable porogen beads,having a diameter of between about 100 micron to about 1000 micron,between about 200 micron to about 800 micron, or a diameter of betweenabout 300 micron to about 700 micron, or a diameter of between about 400micron to about 600 micron.

In some embodiments, the size of the pores of the porous texturedsurface will be somewhat equivalent to the size of the porogens used toform the pores. In some embodiments, at least about 50%, or about 80%,or about 70% ort about 80%, or about 90% of the pores have a diameter ofa uniform size, for example, a diameter of about 100 micron, about 200micron, about 300, micron, about 400 micron, about 500 micron, about 600micron, about 700 micron, about 800 micron, about 900 micron or about1000 micron or greater.

In some embodiments, the pores have a diameter of between about 100micron to about 1000 micron, for example, wherein at least about 50%, orabout 60%, or about 70%, or about 80%, or about 90% of the pores have adiameter in a range of between about 100 micron to about 1000 micron,between about 200 micron to about 800 micron, between about 300 micronto about 700 micron, or between about 400 micron to about 600 micron.

For example, in one embodiment, the first textured surface is defined bypores extending about 2 to about 5 pores deep and about 90% of the poreshave a diameter of between about 400 micron to about 600 micron. Thesecond surface in this and other embodiments may comprise a secondtextured surface defined by pores extending no greater than about onepore deep into the shell outer surface.

In some embodiments, the second surface is a substantially smoothsurface, or a less porous surface, or a less textured surface, or is asurface that allows for less tissue ingrowth, relative to the firsttextured surface.

In one embodiment, a breast implant having a variable textured surfaceis provided, the implant comprising an elastomeric shell comprising afirst region and a second region, an outer surface, and an anterior sideand a posterior side, the first region defined by a first texturedsurface of the shell, the first textured surface being substantiallydefined by interconnected pores extending at least about two to aboutfive pore diameters deep to a depth of between about 0.8 mm to about 3.0mm into the shell outer surface, wherein the pores have a diameter ofbetween about 400 micron to about 600 micron; and the second regiondefined by a second surface of the shell that is different from thefirst textured surface of the shell, the second surface defined by asurface selected from a group of surfaces consisting of a smoothsurface, a second textured surface that is less porous than the firsttextured surface, a third textured surface having concavities extendingno greater than about one pore deep into the shell outer surface, and afourth textured surface having concavities extending less than one poredeep into the shell outer surface.

Further still, such as shown in FIGS. 9-11 to be discussed hereinafter,the first region, comprising a region more textured or more conducive totissue ingrowth, may be disposed on at least a portion of an anteriorside of the shell, and the second region comprising a relatively smooth,or less textured, or less conducive to tissue ingrowth, may be beingdisposed on at least a portion of a posterior side of the shell. Such animplant in accordance with this embodiment is structured to facilitatesurgical removal of the implant from a patient. For example, the implantprovides for easier surgical removal relative to an implant that isfully textured on all of the outer surfaces of the implant.

For example, the first surface of the implant, disposed at least in parton the anterior side of the implant, and having a deeply porous texturethan the second surface, provides a structure for greater tissueintegration and may also reduce capsular formation and/or capsularcontraction. The posterior side of the implant may be smooth or mayinclude a lighter, less porous texture which provides for minimal tissueintegration. In some instances, the pore size of the first texturedsurface and the pore size of the second textured surface may besubstantially the same, with the depth of porosity being the distinctionbetween the two surfaces. In another embodiment, the pore size may bedifferent between the two surfaces, but with the first textured surfaceproviding for greater tissue integration than the second surface.

In these embodiments, the present implant is structured to providecertain aesthetic and surgical advantages over prior art implants.Surgically, for example, the anterior portion of the implant can bereadily accessed through the original incision, for example inframammaryincision, and the integrated tissue can be visualized and surgicallyseparated from the more textured surfaces of the implant. The posteriorside of the implant, which is by nature more difficult to accesssurgically access, can be separated from the tissue by simple fingerdissection of peeling away of the implant due to its minimal tissueintegration. Aesthetically, tissue adherence advantageously can maintaina desired position of the implant in the breast, preventing rotation ormigration, and maintaining correct orientation of anatomically shapedimplants.

FIGS. 9, 10 and 11 show additional embodiments of the invention in whichfirst and second surface textures are located on different regions of animplant in accordance with the invention, and which can provide at leastone or more of the advantages described above with respect tomaintaining correct positioning and facilitating surgical removal ifneeded.

FIG. 9 is a side view of a breast implant 310 in accordance with oneembodiment of the invention. In this embodiment, implant 310 includes afirst surface region 316 and a second surface region 322. Second surfaceregion 322 is different, in terms of texture or smoothness, relative tofirst surface region 316. For example, second surface region 322 isrelatively less textured, less porous, and/or less conducive to tissueingrowth, relative to first surface region 316. In some embodiments, theporosity of first surface region 316 is a multiple-pore depth texture,the porosity of this texture extending from an outer surface 324 of theimplant 310 to a depth that is several pores in depth, for example,about 3, 4 or 5 or more pores in depth. In contrast, second surfaceregion may be relatively smooth, untextured, having open cavities,single-pore depth, or half-pore depth, generally lacking deep cavitiesbeneath the surface, or otherwise lacking significant texture conduciveto tissue ingrowth relative to first surface region 316. As shown, firstsurface region 316 may extend on a portion, for example, on a portion ofthe anterior face of the implant 310, without extending into the outerperimeter region.

FIG. 10 is a side view of a breast implant 410 in accordance with yetanother embodiment of the invention. In this embodiment, implant 410includes a first surface region 416 and a second surface region 422.Second surface region 422 is different, in terms of texture orsmoothness, relative to first surface region 416. For example, secondsurface region 422 is relatively less textured, less porous, and/or lessconducive to tissue ingrowth, relative to first surface region 416. Insome embodiments, the porosity of first surface region 416 is amultiple-pore depth texture, the porosity of this texture extending to adepth that is several pores in depth, for example, about 3, 4 or 5 ormore pores in depth. In contrast, second surface region may berelatively smooth, untextured, having open cavities, single-pore depth,or half-pore depth, generally lacking deep cavities beneath the surface,or otherwise lacking significant texture conducive to tissue ingrowthrelative to first surface region 416. As shown, first surface region 416may extend on a portion, for example, on a lower portion of the anteriorface of the implant 410, and second surface region 422 may extend on aportion, for example, an upper portion, of the posterior face of theimplant 410.

FIG. 11 is a side view of a breast implant 510 in accordance with yetanother embodiment of the invention. In this embodiment, implant 510includes a first surface region 516 and a second surface region 522.Second surface region 522 is different, in terms of texture orsmoothness, relative to first surface region 516. For example, secondsurface region 522 is relatively less textured, less porous, and/or lessconducive to tissue ingrowth, relative to first surface region 416. Insome embodiments, the porosity of first surface region 516 is amultiple-pore depth texture, the porosity of this texture extending to adepth that is several pores in depth, for example, about 3, 4 or 5 ormore pores in depth. In contrast, second surface region may berelatively smooth, untextured, having open cavities, single-pore depth,or half-pore depth, generally lacking deep cavities beneath the surface,or otherwise lacking significant texture conducive to tissue ingrowthrelative to first surface region 516. As shown, first surface region 516may extend on a portion, for example, on a lower and anterior portion ofthe implant 510, and second surface region 522 may extend on theposterior face of the implant 510 as well as portions of the anteriorface of the implant.

Numerous other arrangements are possible and are considered to be withinthe scope of the present invention.

One process for forming flexible implant shells for implantableprostheses involves dipping a suitably shaped mandrel into a siliconeelastomer dispersion. Many such dispersions are used in the field.Basically they contain a silicone elastomer and a solvent. The siliconeelastomer is typically polydimethylsiloxane, polydiphenyl-siloxane orsome combination of these two. Typical solvents include xylene or1,1,1-trichloroethane. Different manufacturers vary the type and amountof the ingredients in the dispersion, the viscosity of the dispersionand the solid content of the dispersion. Nonetheless, the presentinvention is expected to be adaptable to have utility with a widevariety of silicone rubber dispersions.

The mandrel is withdrawn from the dispersion and the excess siliconeelastomer dispersion is allowed to drain from the mandrel. After theexcess dispersion has drained from the mandrel at least a portion of thesolvent is allowed to volatilize or evaporate. Normally this isaccomplished by flowing air over the coated mandrel at a controlledtemperature and humidity. Different manufacturers use variousquantities, velocities or directions of air flow and set the temperatureand humidity of the air at different values. However, the desiredresult, driving off the solvent, remains the same.

An exemplary process for forming the textured surfaces, or fixationsurfaces on a molded silicone shell will now be described. After themandrel is raised out of the silicone dispersion with what is to be thefinal layer adhering thereto, this layer is allowed to stabilize. Thatis, it is held until the final coating no longer flows freely. Thisoccurs as some of the solvent evaporates from the final coating, raisingits viscosity.

Once the flexible shell has been stabilized, any loose fibers orparticles are removed from the exterior of the shell, for example, withan anti-static air gun. A tack coat layer is then applied. The tack coatlayer may be sprayed on, but is desirably applied by dipping theflexible shell on the mandrel into a tack coat dispersion. The operatorimmerses the flexible shell into the dispersion and returns the mandrelto a rack for stabilization. The time required for stabilizationtypically varies between 5-20 minutes. A suitable tack coat layer isdesirably made using the same silicone dispersion material employed inthe base layers.

At this point, dissolvable particles, texturing beads, or porogens (forexample, dissolvable sugar or polymer particles) are applied over thatportion of the exterior surface to be textured. The solid particles maybe applied manually by sprinkling them over the tacky surface while themandrel is manipulated, or a machine operating like a bead blaster orsand blaster could be used to deliver a steady stream of solid particlesat an adequate velocity to the coating on the mandrel. The portion ofthe shell that is not to be textured may be masked during theapplication of the particles. One method of particle application is todip the mandrel/shell into a body of the solid particles or expose it toa suspension of the solid particles.

The tacky flexible shell may then be immersed in a fluidized(air-mixing) aqueous bath of the porogens. After a suitable period ofstabilization, such as between about 5-20 minutes, the shells may bedipped into an overcoat dispersion. A suitable overcoat dispersion maybe made using the same material employed in the base layers. Alternatinglayers of porogens and silicone dispersion may be used to create a depthof texturing desired. The coated shells on the mandrels may then be thenmounted on a rack and allowed to volatilize, such as, for example, about15 minutes.

The entire silicone elastomer shell structure may be vulcanized or curedin an oven at elevated temperatures. The temperature of the oven may bekept between about 200° F. and about 350° F. for a curing timepreferably between about 20 minutes and about 1 hour, 40 minutes. Uponremoval from the oven, the mandrel/shell assembly is placed in a solventfor the porogens, and the porogens allowed to dissolve. The solvent doesnot affect the structure or integrity of the silicone elastomer. Whenthe porogens have dissolved, the assembly is removed from the solventand the solvent evaporated. The shell can then be stripped from themandrel. At this point, it is preferable to place the shell in a solventfor the porogens and gently agitate it to ensure complete dissolution ofall the porogens. When the shell is removed from the solvent, thesolvent is evaporated.

Dissolving the porogens leaves behind open, interconnected, cavities inthe surface of the shell where the porogens had been.

After finishing the shell according to the steps described above, thesteps required to make a finished breast implant prosthesis may besimilar to those known in the art. For example, an opening left by thedip molding process is patched with uncured sheeting, usually made ofsilicone rubber. Then, if the prosthesis is to be filled with siliconegel, this gel is added and cured, the filled prosthesis packaged, andthe packaged prosthesis sterilized. If the prosthesis is to be inflatedwith a saline solution, a one-way valve is assembled and installed, theprosthesis is post cured if required, and the prosthesis is thencleaned, packaged and sterilized. A combination breast implantprosthesis can also be made wherein a gel-filled sac is positionedinside the shell to be surrounded by saline solution.

In one aspect of the invention, a breast implant is provided having moresignificant texturing on the front, or anterior side, of the implant,and is reduced or omitted on the back, or posterior side of the implantto enhance tissue adherence on front of the implant and to reduce tissueadherence to muscle tissue on the back of the implant. For example, insome embodiments, the anterior surface of the implant includes two,three, four, five or more layers of texturing, made for example, byalternating layers of texturing particles with silicone dispersionlayers, during the manufacturing process; and the posterior surfaceincludes one layer of texturing made by application of a single layer oftexturing particles (not alternated with elastomer). Alternatively, theanterior surface includes two or more layers of texturing and theposterior surface having less or no texturing. In any of theaforementioned embodiments, the depth of the porous structure of firstsurface region may be a relatively deep porous structure, for example, aporous structure that is multiple pores deep, for example a depth ofporosity that is about 3, 4 or more pores in depth. In some embodiments,the pore size, for example, the pore diameter, is based on the size ofthe particles used to form the texture.

In some embodiments, about 50%, or about 70% or about 80% or about 90%of the particles used to form the texture are generally spherical beads,for example, dissolvable polymer beads, having a diameter of betweenabout 100 micron to about 1000 micron, for example, about 200 micron toabout 800 micron, for example, or about 300 micron to about 700 micron,or about 400 micron to about 600 micron in diameter.

In one embodiment, about 90% of the particles used to form the pores arebetween about 420 micron to about 595 micron in diameter.

In one particularly advantageous embodiment, the depth or thickness ofthe texture extends between about 0.2 mm to about 5.0 mm, or betweenabout 0.4 mm to about 4.0 mm, or between about 0.8 mm to about 3.0 mm.In one embodiment, about 90% of the particles used to form the pores arebetween about 420 micron to about 595 micron in diameter, and the depthof the porous portion is between about 0.8 mm to about 3.0 mm.

In some embodiments, the texture of the first surface and/or secondsurface are made using polymer microspheres, for example, polymermicrospheres having the aforementioned particle sizes or distributions.In some embodiments, the texturing is accomplished using one or more ofthe processes described in U.S. Pat. No. 8,685,296, issued Apr. 1, 2014,U.S. Pat. No. 8,877,822, issued Nov. 4, 2014, and/or in U.S. patentapplication Ser. No. 13/631,091, filed on Sep. 28, 2012, the entiredisclosure of each of these documents being incorporated herein by thisspecific reference.

For example, a method for making the variable textured implant, forexample, may comprise coating a breast implant mandrel with an elastomerbase, curing the elastomer base to form a base layer, coating the curedbase layer with an elastomer base, coating the elastomer base withporogens to form a porogen layer on the elastomer base. The porogens maycomprise a core material and a shell material surrounding the corematerial. In some embodiments, the porogen comprises a shell materialhaving a melting point temperature that is lower than a melting pointtemperature of the core material. The method may further comprisecoating the porogen coating with another layer of elastomer, coatingthis layer of elastomer with another coating of porogens, (and, ifdesired, repeating the elastomer and porogen coating steps until adesired thickness is built up on the mandrel), treating the elastomerand porogen layers built up on the mandrel to cause the porogens to atleast partially fuse to one another within the elastomer and causing theelastomer to cure, thereby forming a porogen scaffold comprising fusedporogens and cured elastomer. Next, the porogen scaffold is removed fromthe elastomer, for example, by dissolving the porogens using a suitabledissolute. The porogen scaffold removal results in a textured implantshell having a textured surface comprising interconnected pores. Thismethod may include masking portions of the implant shell during thelayering steps to keep the other regions of the implant untextured, e.g.matte, thus producing a breast implant shell having a texture on only afirst region of the implant, with a balance of the implant surface beinguntextured, or matte. Alternatively, the masked portion may be unmaskedafter the first region has been textured, and the unmasked portion maythen be textured using a process different from the first regiontexturing process, or similar thereto but with fewer layers, forexample. For example, after the first region has been textured, theunmasked portion may be layered with only one layer of porogens toproduce a second region that has a lightly textured surface, or feweralternating layers of elastomer and porogens may be used to produce aless textured, less porous, second region of the implant. Many differentcombinations of these steps may be used to produce the final variabletextured implant as described elsewhere herein and having one or more ofthe surgical and/or aesthetic advantages described herein.

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the scope of the invention, ashereinafter claimed.

What is claimed is:
 1. A breast implant comprising: an elastomeric shellcomprising a first region and a second region, and an outer surface; thefirst region defined by a first textured surface; and the second regiondefined by a second textured surface, the second textured surfacedefined by open pores extending no greater than about one pore deep intothe shell outer surface; the first textured surface being defined byinterconnected pores extending about two to about five pores deep to adepth of between about 0.2 mm to about 5.0 mm into the shell outersurface.
 2. The implant of claim 1 wherein the pores have a diameter ofbetween about 100 micron to about 1000 micron.
 3. The implant of claim 1wherein at least about 70% of the pores have a diameter of between about100 micron to about 1000 micron.
 4. The implant of claim 1 wherein atleast about 90% of the pores have a diameter of between about 100 micronto about 1000 micron.
 5. The implant of claim 1 wherein the pores have adiameter of between about 200 micron to about 800 micron.
 6. The implantof claim 1 wherein the pores have a diameter of between about 300 micronto about 700 micron.
 7. The implant of claim 1 wherein the pores have adiameter of between about 400 micron to about 600 micron.
 8. The implantof claim 1 wherein at least about 90% of the pores have a diameter ofbetween about 400 micron to about 600 micron.
 9. The implant of claim 1wherein the first textured surface is defined by interconnected poresextending two to five pores deep.
 10. The implant of claim 1 wherein thecomprise negative impressions of texturing particles.